Piston and piston ring



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H. B. JOHNSTON.

PI-STON AND PISTON RING.

APPLICATION FILED APR115. 1922.

Patented June 6, 1922.

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H. B. JOHNSTON.

PISTON AND PISTON RING. APPLICATION FILED APR. 15, 1922.

Patented June 6, 1922.

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PISTON AND PISTON RING.

APPLICATION FILED APR 15, 1922.

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PATENT @FFHCE.

HARRY B. JOHNSTON, OF SEATTLE, WASHINGTON.

PISTON AND PISTON RING.

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Application filed April 15,

To all whom it may canoe)..-

Be it known that I, HARRY B. JOHNSTON, residing at Seattle, county of King, State of Washington, a citizen ofthe United States, have invented certain new and useful Improvements in Pistons and Piston Rings, of

' pressure at the end ofthe piston to reach which the following is a specification.

This invention relates to pistons and piston rings and has particular relation to pistons and rings for use in c linders where it is necessary to maintain a t1 ht seal between the iston and cylinder walfi T 1e primary object of my invention is the provision of an improved piston having a groove with an inclined wall, a. ring in the groove and an improved method of permitting the pressure, at the end of the cylinder, to come into contact with the ring in a manner to facilitate the proper seating of the ring with the cylinder wall.

Another object of my invention is the rovision of an improved hollow piston liaving a groove with an inclined wall, .a ring in the groove and having outwardly divergent opposite walls, the piston being rovided with a communication between the interior of the piston and one side of the ring, the piston having a cylindrical cylinder bearing surface on each'side of the ring.

Another object of my invention is'the production of a piston having means for preventing over oiling in, for instance, an internal combustion motor.

Still another object is the provision of an imgroved ring joint.

ther and further objects will be apparent a the structure is understood.

Referring to the drawing wherein preferred forms of my invention are illus- Figure 1 is a section of a piston illustrating my invention.

Figure 2 is an elevation of the embodiment of my invention illustrated in Fig. 1.

Figure 3 is a sectional view of a modified form of Fig. 1. i Figure 4 is an elevation of the form shown in Fig. 3.

Fig. 5 is amodified form of piston illustrating the adaptation of the ring and groove shown inFig. 1, to both ends of the piston.

Fig. 6 is a broken view of the r111 Referring to Figs. 1 and '2 1O designates a piston having a head 11. Th vided with a groove-13 havmg an inclined wall 14 on the side opposite the adjacent Specification of Letters Patent.

at least a portion within the bore.

e piston is pro-' Patented June 6, 1%22. 1922. Serial no. 552,944.

end of the piston. A split ring 15 is provided for the groove and has an inclined surface 16 which corresponds to and contacts wlth the inclined wall 14 of the groove 13. The head 11 is cut away adjacent its outer periphery in such a manner as to permit the the surface 17 of the ring 15. The oppositely disposed surfaces 17 and 16 are outwardly divergent relative to each other. The ring fits the groove in such a manner that preferably when compressed to its inward position, it is at or slightly within the periphery of the piston.

Intermediate the ends of the piston and shown in Fi ures 1 and 2 on the opposite side of the wrist pin hole 18, from the groove 13, is a groove 19 having a split ring 20 for cooperation therewith. The roove 19 is provided with an inclined wal 21 which is oppositely inclined relative to the inclined wall 14 of the groove 13.

The ring 20 is preferabl fitted to its groove 19 in such a manner t at when compressed, its peri hery will be at or slightly within the periphery of thepiston.

The ring has an inclined surface 22 in contact with the inclined wall 21 of the groove.

'Connnunicating with the surface 23 of the ring are holes 24 which are bored through the piston wall into and communicating with the interior of the piston. A suitably sha ed channel 25 is provided to permit the 'sur ace of the ring to be affected by the "able to have the skirt portion 26 of the pis ton extend out beyond the cylinder bore at one end of the stroke while obviously the ring at the end of the stroke must extend The action of the ring 15 in the groove 13 is as follows The pressure at the end of the piston comes into contact with the surface 17 of the ring 15. This pressure downward presses the ring along the inclined surface 14, outwardly against the cylinder wall. This action causes a tight seal to be efiected between the piston and ring through contact between the inclined surfaces 14 and 16. At the same time, a tight seal is effected between the ring and cylinder wall, all excess oil being forced along with the movement of the ring. \Vhile in the ordinary construction, the tendency of the rings is to collapse in the construction shown in the drawing, the tendency is always to expand the ring when the pressure comes from the right direction.

The operation of the ring 20 in its groove 19, when applied, for instance, to an internal combustion motor, is as follows On the power stroke, the friction between the ring 20 and the cylinder wall, caused by the spring tension of the ring, causes the rm to act as a check valve, because of the inc ined surfaces, and effectively holds the ring aganst the cylinderwall. This tends to scrape any oil, which may be present on the cylinder wall, into the channel 25 and into the openings 24. The oil drains along the inside wall of the piston to the edge 27 from where it drops into the crank case. At the bottom of the piston is a groove 28 which also aids in preventing overoiling of the pistons.

During the suction stroke, the piston is moving downward, atmospheric pressure enters through the openings 24 and presses upon the ring 20 causing it to have a tendency to move outwardly along the inclined seat and eifectively seat against the cylinder wall. Any oil which might be present on the wall of the c linder is scraped downward, it being dralned out from the holes 24 or at the 'outer lower edge of the piston.

In Figures 3 and 4 is illustrated a form of the invention wherein the piston 10 is provided with a head 11*, a groove 13*, the groove having an inclined wall 14*. A ring 15 is provided in the groove 13 and has an inclined surface 16 and an opposite surface 17 outwardly divergent with relation to the surface 16. The piston is provided with a wrist pin hole 18*. A groove 19 is provided on the same side of the Wrist pin hole 18 as the groove 13. This groove 19 is provided with a ring 2O having an inclined surface 22 engaging an inclined wall 21 of the groove. An opposite surface 23 is provided, being outwardly divergent with relation to the inclined surface 22 in contact with the wall 21 of the groove. Adjacent the groove 19 is a channel 25 having openings 2a communicating with the interior of the piston. The skirt tive rings. The ring grooves have adjacent channels 25 which are provided with openings 24 which extend through the wall to the interior of the piston. In the form shown in Fig. 5, a iston rod is secured in the web 10 by t e nut 31 on the screw threaded end 32-0f the rod.

In Figure 6, is shown a ring partly broken away and showing the step Sq'oint 31 which is shown as a preferred form of step joint as its construction is one which ensures maximum strength.

The actions of the rings 20 and 20 are similar to the action of the ring 20 and ,will

not be repeated in full.

While I have described embodiments of my invention in detail, I desire to have it understood that I do not limit myself tothe exact structures shown and that modifications and chan es may be made without departing from tie spirit of my invention and within the scope of the appended claims.

Having described my invention, what I claim is 1. A hollow piston having a groove, the groove having an inclined wall, the wall of the piston being provided with a hole to communicate with the groove to permit the pressure of the interior of the piston to communicate with the groove, a metallic ring in the groove, the ring havin an-inclined surface to cooperate with the inclined wall of the groove.

2. A hollow piston having a ring groove, the groove having an inclined wall, a rin in the groove and having an inclined sur ace cooperating with the inclined wall of the groove, the piston having a channel adjacent the ring groove and openings from the channel to the interior of the piston.

In testimony whereof I hereunto aflix my signature.

HARRY B. JOHNSTON. 

